Din 76-a Pdf !link! -

(Undercut Diameter): The diameter of the recessed portion. It is always smaller than the minor diameter of the thread. (Undercut Width): The longitudinal width of the recess.

The standard provides a lookup table based on the thread pitch (). For any given pitch, DIN 76-A specifies three primary dimensions:

(Radius): The curvature at the base of the undercut to prevent sharp corners that lead to fatigue cracking. Table: Common DIN 76-A Dimensions (Partial) Thread Pitch (P) 📋 Types of Undercuts in DIN 76 din 76-a pdf

A Type A undercut is deeper and wider than Type B. While Type A provides better clearance for the mating part, it reduces the cross-sectional area of the bolt more than Type B. In high-stress applications, verify that the reduced diameter ( ) can handle the tensile load. 2. Manufacturing Methods

Are you trying to decide between and Type B (short) for a tight assembly? (Undercut Diameter): The diameter of the recessed portion

If the threads are rolled rather than cut, the undercut requirements might change. However, DIN 76-A remains the "gold standard" for general machining to ensure compatibility across different manufacturers. 3. Annotation on Drawings

This is the official source for all DIN standards. The standard provides a lookup table based on

DIN 76-1 defines the shapes and dimensions of thread undercuts. The "Type A" designation specifically refers to the standard undercut for external metric threads. Why Use an Undercut?

Short undercut for external threads (used when space is limited).

Because DIN standards are copyrighted, "free" PDFs found on the web are often unauthorized or outdated. To ensure your engineering team is working with the most current data, you should: